The present invention relates to a torque converter (T/C) including a converter cover to which power is transmitted from a rotation drive source such as an engine, and specifically to a T/C in which a starter ring gear for initiating the rotation drive source is firmly connected with a converter cover.
A T/C of a related art is shown in FIG. 4. As illustrated in FIG. 4, converter cover 54 of torque converter 53 is connected with drive plate 51 via connection 52 therebetween. Drive plate 51 is connected with an engine output shaft. Starter ring gear 55 is welded at 56 to an outer circumferential surface of converter cover 54. Starter ring gear 55 is driven by a starter motor by meshing with a pinion mounted to the starter motor.
If a rim of starter ring gear 55 has a relatively small thickness, teeth formed on an outer circumferential surface of starter ring gear 55 will be readily heated by heat produced upon welding, and then be cooled down to ordinary temperature. As a result, the teeth of the starter ring gear 55 is annealed so that the rigidity will be deteriorated. This will facilitate abrasion of the teeth of the starter ring gear 55 which is caused by meshing with the pinion mounted to the starter motor.
It would threrefore be desirable to provide a method of connecting a starter ring gear with a converter cover within a T/C without using welding. The method can prevent the starter ring gear from being deteriorated in rigidity due to annealing after welding, serving for reducing abrasion of teeth of the starter ring gear which is caused upon meshing with a pinion of a starter motor. Further, it would be desirable to provide a T/C in which a starter ring gear is connected with a converter cover without using welding, whereby the starter ring gear can hold a good rigidity and can be less affected by abrasion of teeth thereof which is caused upon meshing with a pinion of a starter motor, so that the life of the starter ring gear can be prolonged.
In one aspect of the present invention, there is provided a method of connecting a starter ring gear with a converter cover within a torque converter, the starter ring gear being adapted for initiating a rotation drive source for the torque converter and rotatable about a rotation axis, the starter ring gear including a first engaging member disposed on an inner circumferential surface of the starter ring gear, the converter cover being rotatable about the rotation axis together with the starter ring gear, the converter cover including a cylindrical wall extending along the rotation axis, a disk wall connected with an axial end of the cylindrical wall to form a corner portion therebetween, and a second engaging member which is engaged with the first engaging member and disposed on an outer circumferential surface of the cylindrical wall, the method comprising:
setting the starter ring gear at the corner portion between the disk wall and the cylindrical wall of the converter cover in alignment with each other; and
producing a plastic flow of metal at the corner portion between the disk wall and the cylindrical wall of the converter cover, the plastic flow of metal forming the second engaging member engaged with the first engaging member, to thereby connect the starter ring gear with the converter cover.
In a further aspect of the present invention, there is provided a torque converter in connection with a rotation drive source, the torque converter including a starter ring gear adapted for initiating the rotation drive source and rotatable about a rotation axis, the starter ring gear including a first engaging member disposed on an inner circumferential surface of the starter ring gear, and a converter cover rotatable about the rotation axis together with the starter ring gear, the converter cover including a cylindrical wall extending along the rotation axis, a disk wall connected with an axial end of the cylindrical wall to form a corner portion therebetween, and a second engaging member which is engaged with the first engaging member and disposed on an outer circumferential surface of the cylindrical wall, the starter ring gear being connected with the converter cover by a method comprising:
setting the starter ring gear at the corner portion between the disk wall and the cylindrical wall of the converter cover in alignment with each other; and
producing a plastic flow of metal at the corner portion between the disk wall and the cylindrical wall of the converter cover, the plastic flow of metal forming the first engaging member engaged with the second engaging member, to thereby connect the starter ring gear with the converter cover.